Why Do Fish Have Scales?
All living creatures in this world, the animals and humans have a protective outer covering of the body. In humans it is called the skin, in animal’s fur and scales. Each has its own purpose and is unique in different species. They are important and hold qualities that help the different species survive in their respective environments.
There are land animals that have scales as well and this includes the reptile family of snakes and lizards. But when you say the word ‘scales, you would initially think about aquatic creatures like fish and other marine animals that live on the water. Contrary to the popular belief, not all fishes have scales. Scales come in different shape, color and sizes as well.
There are many types of scales. These include Placoid scales, Cosmoid scales and Ganoid scales.
Placoid scales are scales that can be as hard as teeth. They are also called dermal denticles and are present in sharks, rays and other sea creatures. Cosmoid scales are the scales of bony fishes. An example is the extinct Crossopterygians. Ganoid scales on the other hand are scales that are found in most fishes. They are shiny, hard and diamond shaped.
The primary use of scales for the fish is ‘external protection,. Genders can sometimes affect the type of scale a fish possess. This is true when it comes with flounders and other types of flat fishes.
As the fish grows, their scale grows with them. Some species have lesser and denser scales compared to others which enable them faster movement in the water. Evolution has played a big role on the present scales of land and aquatic life world wide. Evolution doesn’t stop here and the scales of fishes will continually change to suit the environment that they live in. You can also call them the fish’s ‘personalized, chain mails.